Alternating copolymers of ethylene with cyclo-olefins



May 28, 1968 NATTA ET AL 3,385,840 4 ALTERNATING COPOLYMERS OF ETHYLENE WITH CYCLO-OLEFINS Original Filed July 5, 1962 u I I 5 l I 20 (Cu Kod X-RAY SPECTRUM OF AN ALTERNATING THREO-Dl-SYNDIOTACTIC COPOLYMER 0F ETHYLENE AND CYCLOPENTENE INVENTORS. GIULIO NATTA GINO DALL'ASTA GIORGIO MAZZANTI ITALO PASOUON ALBERTO VALVASSORI ADOLFO ZAMBELU United States Patent 11 c1aims.(cl. 26088.2)

This application is a continuation of application Ser. No. 207,598, filed July 5, 1962, and now abandoned.

This invention relates to new high molecular weight copolymers of ethylene with cyclo-olefin's, and to a process for producing them.

It was not apparent that high molecular weight linear copolymers of ethylene with cyclo-olefins could be produced.

The typical anionic catalysts for the low-pressure polymerization of ethylene and alpha-olefins, for instance those prepared from transition metal compounds and organometallic compounds of metals of Groups I-A, II, and III-A of the Mendeleef Periodic Table, do not promote the homopolymerization of cyclo-olefins.

Unexpectedly, we have found that true copolymerizates comprising solid, high molecular weight, linear copolymers of ethylene with cyclo-olefins containing 4 to 8 carbon atoms, or with their nuclearly alkylated derivatives in which the alkyl groups contain from 1 to 6 carbon atoms and are bound to a carbon atom not involved in a C=C linkage, can be obtained by contacting a mixture of the co-monomers under particular conditions with anionic catalytic systems prepared from specific compounds of transition belonging to Groups IV, V or VI of the Mendeleef Periodic Table and organornetallic compounds of rnetals belonging to Groups I-A, II or III-A of said table.

Transition metal compounds that can be used in preparing the catalyst are TiCl TiCl (which can be obtained, e.g., by reducing TiCl, with hydrogen, aluminum, or with aluminum alkyls under particular conditions), TiI VCh, VOCl vanadium triacetylacetonate, vanadyl diacetylacetonate, alkyl orthovanadates, e.g., ethyl orthovanadate, chromyl chloride, and chromium acetylacetonate.

Organometallic compounds that are useful catalystforming components for our purposes include Al(C H 4 9)2; a 'z)2 2 5)2 2 5)2;

and Al(C H )X Y wherein X is any halogen and Y is an electron-donor, e.g., a tertiary or secondary amine, an onium sal or an alkaline halide.

The copolymerization is carried out in a liquid diluent which may be an inert aliphatic or aromatic solvent, or the liquid cycle-olefin to be copolymerized.

The copolymerization can be effected at temperatures ranging from 80 C. to +100 C. The preferred temperature is in the range from -50 C. to +10 C.

Depending upon the specific components from which it is formed, the catalyst may be colloidally dispersed, finely dispersed, or completely dispersed (dissolved) in the liquid phase in which the copolymerization takes place. For example, heterogeneous catalysts prepared from TiCl, and e.g., an Al trialkyl or dialkyl Al halide are usually colloidally dispersed in the liquid phase, whereas homogeneous catalysts prepared from hydrocarbon-soluble transition metal compounds, particularly certain of the hydrocarbon-soluble vanadium compounds, and particular organometallic compounds, are usually completely dispersed in the hydrocarbon liquid phase to provide a homogeneous copolymerization system. The preferred catalytic systems for use in our present process are finely dispersed catalysts freshly prepared at low temperature from (1) VCl or VOCl and Al trialkyls, or homogeneous catalysts freshly prepared at low temperature from (1) vanadium triacetylacetonate, vanadyl diacetylacetonate, vanadium ch'l-oroacetylacetonate, or an alkyl-orthovanadate, and (2) a dialkyl Al monohalide.

For the heterogeneous finely dispersed catalysts, the preferred organometallic compound/ transition metal compound molar ratio is between 2:1 and 3:1; for the homogeneous catalysts, said molar ratio is higher than 4:1 and preferably between 4:1 and 10: 1.

It is desirable to maintain a constant relative concentration of the ethylene and cyclo-olefin to be copolymerized in the liquid phase during the copolymerization reaction, in order to obtain copolymers having a composition as homogeneous as possible. This can be accomplished conveniently by carrying out the copolymerization continuously, by continuously feeding the comonomers and discharging the copolymerizate formed, or by recycling the mixture of the co-monomers to be copolymerized at appropriate rates.

Cyclo-olefins containing up to 8 carbons atoms in the cycle can be copolymerized according to our invention, i.e., cyclobutene, cyclopentene, cyclohexene, cycloheptene, and cis and trans cyclo-octene.

Alkyl cyclo-olefins which can be copolymerized with ethylene by our method include 4-methyl-cyclopentene-l, 3-methyl-cyclohexene-l, 4,S-dimethyl-cyclohexene-1.

In the copolymers we obtain, the units derived from the cyclo-olefin are linked, at both ends, to methylene groups and sequences of two or more derived from the cyclo-olefin are not present in the main chain. In fact, the cyclo-olefins (except for cyclo-butene) do not form ho-mopolymers in the presence of the catalysts used in our process. Only in case of ethylene-cyclobutene copolymers direct enchainment between cyclo-olefin units is possible. Moreover, we have observed that even with very low molar ratios between the ethylene and cyclo-olefin (except for cyclobutene) present in the liquid phase, copolymers containing more than 50% by mols of rnonomer units deriving from the polymerization of the cyclo-olefin are not obtained.

The properties of the copolymers depend, in the first instance, on the cyclo-olefin content and, in the second instance, on whether or not the copolymers show a regular steric distribution of the tertiary carbon atoms present in the units derived from the cycle-olefin along the macromolecular copoly meric main chain.

When the cyclo-olefin content is low, generally below 20% by mols, the copolymers consist of macromolecules in which the relatively low percentage of cycle-olefin units are distributed randomly along the main chain, and the copolymers exhibit only a crystallinity of the polyethylene type (due to sequences of methylene groups) when examined under the X-rays at room temperature. Such copolymers are, however, very different in their properties from the homopolymer, polyethylene. The percent crystallinity and melting point of the copolymers, as well as their infra-red spectrum, are diiferent from those of polyethylene per se, both the melting point and crystallinity being lower than the melting point and crystallinity of the homopolymer.

The crystallinity of the polyethylene type exhibited by said copolymers decreases sharply (more particularly macromolecule, and our copolymers containing from 30 to 50 mol percent of the cyclo-olefin in the macromolecule can exhibit a crystallinity of a type very different from the polyethylene type and which cannot be ascribed to sequences of methylene groups.

Our crude copolymerizates are usually mixtures of the copolymers consisting of the macromolecules containing only a relatively small proportion of cyclo-olefin units and which units are distributed randomly along the main chain, and copolymers consisting of macromolecules the main chains of which contain groups of the following type in which the R radicals are hydrogen or the same or different alkyl groups containing from 1 to 6 carbon atoms, and n can be zero or an integer from 1 to 4.

The copolymers consisting of the macromolecules containing groups of type (I) in the main chain have a regular chemical structure and are more or less regularly alternating copolymers to the extent that groups of type (I) appear in immediate succession in the main chain, being pure or essentially pure alternating copolymers of completely regular chemical structure when the cyclo-olefin and ethylene are present in the macromolecule in equimolar ratios.

In many cases, our copolymers substantially consisting of macromolecules containing groups of type (I) in the main chain, and comprised in our crude copolymerizates, show both a regular chemical structure resulting from successive repetition of groups of type (I) at least for long portions or stretches of the main chain and a regular steric distribution of the tertiary carbon atoms present in the units deriving from the olefin for sections of the main chain made up of the successively repeating groups of type (I) at least sufficiently long to cause the formation of the lattice of a crystallite. Those copolymers exhibit, when examined under the X-rays at room temperathe copolymers having a low content of units deriving from the cyclo-olefin which were randomly distributed along the main chain, and copolymers consisting of macromolecules containing groups of type (I) in the main chain, which latter copolymers predominated in the crude copolymerizates.

Cyclopentene is a cyclo-olefin which when copolymerized with ethylene according to the present invention yields a crude copolymerizate comprising the aforesaid dilferent kinds of copolymers, and from which the different kinds of copolymers can be separated by fractional dissolution.

The invention will be discussed in relation to the ethylene/cyclopentene copolymerizates, for illustrative purposes.

When we copolymerized ethylene/cyclopentene mixtures (Examples 17 hereinbelow) in which the molar ratio of the co-monomers was such that the cyclopentene content of the copolymerization product was lower than mol percent, the crude copolymerizate, while being very difierent from polyethylene in its overall properties, nevertheless exhibited only a crystallinity of polyethylene type and attributable to the presence in the main chain of sequences of methylene groups deriving from polymerization of the ethylene.

By using starting ethylene/cyclopentene mixtures of a molar ratio (e.g., :1) such that the copolymerizate contained a higher proportion (over mol percent of the cyclopentene), we obtained a crude copolymerizate which, when examined under the X-rays at room temperature, exhibited a crystallinity of a type different from polyethylene crystallinity, and which is illustrated in the accompanying drawings showing the spectrum we attribute to a regularly alternated, sterically ordered ethylene-cyclopentene copolymer, according to our invention and in which the tertiary carbon atoms have a regular steric configuration, as shown in the following model of a portion of the main chain of such an ethylene/cyclopentene copolymer:

H 2 Hz ture, more or less crystallinity of a type very different from polyethylene crystallinity and which must be attributed to the regular steric distribution of the tertiary carbon atoms of the cyclo-olefin units.

Our copolymers consisting of macromolecules containing equimolar ratios of the cycle-olefin and ethylene, and

which show the required regular steric distribution of the tertiary carbon atoms of the cyclo-olefin units are pure or essentially pure alternating copolymer with a completely regular chemical structure and which also exhibit a very high percent of the crystallinity of non-polyethylene type when they are examined under the X-rays at room temperature.

Our copolymers consisting of macromolecules containing the cycle-olefin and ethylene in equimolar ratios but which do not show a regular steric distribution of the cyclo-olefin units are pure or essentially pure alternating copolymers with a regular chemical structure but which are substantially amorphous when examined under the X-rays at room temperature.

The copolymers consisting of the different kinds of macromolecules which are present in admixture in our crude copolymerizates have diiferent solubilities in organic solvents and can be separated as fractions from the mixture by subjecting the crude copolymerizates to fractional dissolution.

We have copolymerized ethylene/cyclo-olefin starting mixtures in which the ethylenezcyclo-olefin molar ratio in the liquid phase was between 200:1 and 25:1 (ethylene partial pressures between 25 and 200 torr) and obtained, in each case, copolymerizates comprising a mixture of B20 H2 Hz Hg CH2 OIL;

By subjecting said ethylene/cyclopentene crude copolymerizate to fractional dissolution, we obtained copolymers consisting of macromolecules containing 50% by mols of cyclopentene and the composition of which corresponds to that of a copolymer in which the two monomers are present in equimolar amounts.

The crude copolymerizates of ethylene and cyclopentene produced according to our invention and having a cyclopentene content equal to or slightly lower than 50 mols percent, exhibit the type of crystallinity shown in the drawing and, by extraction with boiling solvents, give fractions having a cyclopentene content of practically 50 mols percent, independently of the solvent which is used for the fractionation, and which can be made up of macromolecules which exhibit more or less crystallinity corresponding to a regular steric structure and whose molecular Weight is more or less high.

By fractionating such crude copolymerizates by successive extractions with ditferent boiling solvents, we obtained copolymers which were highly crystalline as determined by X-ray examination. For instance, using ether, n-hexane, n-heptane and n-octane as the successive extracting solvents, we obtained the following fractions:

(1) Ether extracts having an oily or waxy consistency and consisting of low molecular weight regularly alternated copolymers of regular chemical structure which contained about 50% by mols of cyclopentene but showed no regular steric distribution of the tertiary carbon atoms of the units derived from the cyclopentene and were, consequently, completely amorphous on X-ray analysis;

(2) n-Hexane extracts consisting of copolymers having a cyclopentene content of about 45-50% by mols, and which were plastic, substantially completely amorphous solid copolymers, or solid copolymers which exhibited a weak crystallinity of the non-polyethylene type shown in the drawing;

(3) n-Heptane extracts consisting of solid copolymers containing about 40 mols percent of cyclopentene and which exhibited some crystallinity of the type shown in the drawing;

(4) n-Octane extracts consisting of powdery solid copolymers having a cyclopentene content between 35 and 50% by mols, and which exhibited a high percent of crystallinity of the type shown in the drawing, as well as crystallinity of the polyethylene type; and

(5) A residue of the n-octane extraction consisting of solid, powdery copolymers having a 'eyclopentene content of about 50% by mols and which exhibited a very high crystallinity of the type shown in the drawing (in general a crystallinity over 50%) and no crystallinity of the polyethylene type; these copolymers were practically pure alternated copolymers having a high regularity of steric structure of the tertiary carbon atoms.

A constant increase was observed in the percent crystallinity of the type shown in the drawing (characteristic of a sterically regular alternated copolymer) exhibited by the successively extracted fractions, the maximum of such crystallinity being found in the residue of the n-octane extraction.

Taking into account that no crude copolymerizate or fraction thereof obtained by us contained more than 50% by mols of cyclopentene, the content of monomeric units deriving from cyclopentene in the n-octane residue, the crystalline structure of those copolymers, and their infrared spectrum, all support the conclusion that the copolymers non-extractable with the solvents used and remaining as residue of the n-octane extraction consist of macro molecules made up, at least for very long sections of the main chain, of regularly alternated and sterically ordered monomeric units deriving from ethylene and cyclopentene.

The regularly alternated, sterically ordered copolymers of ethylene with cyclopentene have the following properties:

Cyclopentene molar ratio percent 50 Density at 24 C. 1.01 Melting temperature C 183-185 Solubility:

insoluble (both at room temperature and at the boiling point) in e.g., methanol, ethyl ether, n-octane, acetone, methylethylketone, glacial acetic acid, dioxane, dimethylforrnamide, carbon tetrachloride, soluble at the boiling point of the solvent but insoluble at room temperature in e.g., benzene, toluabsorption of CH groups in the chain (bands at 684 intense band at 13.2.1.0 (methylenic sequences of two carbon atoms);

complete absence of bands at 13.6 and 13.9;r (methylenic sequences of more than two carbon atoms).

X-ray examination on powders:

main reflections at lattice distances of 5.83 A., 4.92

X-ray examination on fibers subjected to stretching and annealing:

identity period along the fiber axis-=9.0 A.i0.2

orthorhombic elementary cell lattice constant: a=8.75 A.; b=7.83 A.; c=9.0 A.

chain structure: not yet cleared up; presumably erythro-diisotactic or three-disyndioactic.

The stereoregular structure we assign to the regularly alternated, sterically ordered copolymers which constitute a high proportion of our crude ethylene/cyclopentene copolyme-rizate, is contained in more or less considerable amounts in the n-hexane, n-heptane and n-octane extracts and macromolecules having such stereoregular structure are practically the sole constituents of the n-octane residue. Such structure (which is illustrated in the model hereinabove) is in conformity with the following facts:

(a) Even if the ethylene partial pressure during the copolymerization is reduced, the cyclopentene molar content of the crude copolymerizate does not exceed 50% but approaches asyntotically that value (the theoretical value corresponding to the completely alternated copolyrner being 50% (b) By fractionating such a crude copolymer having a oyclopentene molar content of about 40-47%, the fractions obtained do not present a cyclopentene molar content higher than 50% and some of them (ether extract, nhexane extract, n-octane extraction residue) present a cyclopentene molar content of about 48-50%;

(0) By further fractionating a fraction containing exactly 50% by mols of cyclopentene, e.g., by fractional precipitation from a Warm toluene solution all of the fractions obtained have a cyclopentene molar content of 50%;

(d) The presence of a high crystallinity, characteristic of a new crystalline entity, which reaches its maximum intensity in correspondence with a cyclopentene molar content of 50%;

(e) The crystallographic structure of the product, determined from the spectrum of oriented fiber;

(f) The substantial identity of the density determined experimentally (d *=1.0l) and of that calculated on the basis of the orthorhombic cell (having lattice constants a=8.75 A.; b=7.83 A.; c=9.0 A.) (d =l.O3);

(g) The presence of an infra-red absorption band characteristic of methylenicsequences containing two CH groups, and the contemporaneous absence of bands characteristic of methylenic sequences with more than two CH groups;

(h) The impossibility of preparing cyclopentene homopolymers with the aid of the catalytic systems employed in the process of the present invention, which militates against the occurrence of sequences of cyclopentene monomeric units in the copolymer macromolecule.

By copolymerizing ethylene with other cyclo-olefins, we obtained results similar in many respects to those we obtained with ethylene and cyclopentene. For instance, by copolymerizing ethylene with cyclohexene, cycloheptene or cyclo-octene by the process of this invention, we obtain copolymers the macromolecules of which contain ethylene units and units derived from the cyclo-olefin in various ratios depending on the copolymerization conditions. Our crude copolymerizates of ethylene with cycloheptene comprised copolymers consisting of macromolecules essentially characterized by the regularly, successively alternating occurrence of ethylene units and units derived from the cycloheptene in the main chain, with the pair of tertiary carbon atoms in successive units from the cycloheptene having, at least for long sections of the main chain, the steric order which characterizes the stereoregular structure.

The copolymerization of cyclo-olefins according to the process object of the present invention involves double bond cleavage and the units derived from it are saturated;

the copolymers obtained are therefore made up of methylin the 3 aforementioned cases, the following partial one group and cycloalkane groups. pressures:

The ethylene-cyclobutene copolymers distinguish them- (1) Ethylene partial pressure-1100 torr, nitrogen-iselves from the other abovementioned ethylene-cycloolesolvent-l-cyclopentene partial pressure=750 torr fins or ethylene-alkylcycloethylene copolymers; it is in (2) Ethylene partial pressure-=50 torr, nitrogen+solvfact possible to obtain such copolymers having all ethylent+cyclgpgntane=750 t cue to cyclobutene molar ratios comprised between 99:1 (3) Ethylene partial pressure=25 torr, nitrogen-l-solvand 1:99. It is therefore most likely that in these ethylene/ ent+cyc1opchtehe i l =750 t eyeiohutehe eopoiymefs y exist direct eheheihiheht Since the conversion of cyclopentene is rather limited, tween cyclobutene units. No crystallinity peak attributable h variations i h i i h ratio between h concen. t0 alternating eepeiylhefs has been found, not even in the tr-ations of ethylene and cyclopentene are small. The cocase of 1:1 molar ratio between the two monomeric units polymerization ti i 11 f E l 1 t 6 i 7 h r in the p y With higher ethylene hits Content, Y The equilibrium between ethylene in the gaseous phase tallinity characteristic Of P y y sequences pp and that present in the liquid phase is constantly assured Our new ethylene/cyclo-olefin copolymers which con- 15 b a vigorous i ti sist of the macromolecules exhibiting crystallinity due to h copolymerjzation i t d b pouring the the regular steric distribution of the cycle-olefin units in action product into an excess f methanol 500 com the main chain are Plastic hfltttefials and can be Used, fer taining 5 cc. of cone. hydrochloric acid. After some hours example for the Production of fibers, iiime, and other the precipitated copolymer is filtered, washed with boilmahutfletufed Shaped eftleiesour ethylehe/eyeieoiefih 0 ing methanol and dried under reduced pressure at 100 C.

p y consisting 0f amorphous or ehhstehtiaiiy enter The ethylene content of the copolymer is determined by Phone macromolecules have eiestomerie Properties and radiochemical analysis and the cyclopentene content is can he used for those P p to which eiaetomel's are directly determined by infra-red analysis from the ratio p between the intensity of the absorption of the cyclic The following examples are given to illustrate our methylehih groups and h of h absorption f h lhvehtiohopen-chain methylenic groups (absorption bands at 6.93

EXAMPLES 1 t0 6 and at 6.84/1. of the infra-red spectrum registered with The copolymerization vessel consists of a 200 cc. cylinz Optics)- drical apparatus provided with a side tube and cock for The copolymerization conditions of Examples 1 to 6 feeding ethylene. Air is completely removed from the and the results obtained are reported in Table 1.

TABLE l..-COPOLYMERIZATION OF CYCLOPENTENE WITH EIIIYLENE Cyclopentene C2114, Copolymcr [n] at 135 C. molar content Example Catalyst Torr obtained, g. in tetrahydroin the crude pressure naphthalene product,

percent 1.- VCl4/Al(hcxyl)3 100 4.29 1.74 30.2 2.- ..do

50 1.97 0.98 45.2 .do 25 0.97 0.90 47.2 4-- V(acetylacetonate) /AlEtgCl.-- 100 2. 41 2. 25 35.7 5-. do 0. 97 0.86 44. 7 6 do 25 0.44 0 89 46.3

1 Determined by radiochemical analysis and confirmed by infra-red spectrophotometry. vessel and replaced by anhydrous nitrogen. The reaction The products obtained according to the conditions reapparatus is then completely immersed in a bath kept at ported in Table 1 consist of ethylene-cyclopentene coaconstant temperature of 3() c, polymers whose cyclopentene content decreases by in- The apparatus is then agitated by means of a shaking 45 creasing the ethylene partial pressure used in the copolymdevice (90l00 shakes/minute). erlzatlon.

10.0 g. (0.147 mol) of pure cyclopentene, previously In all the above examples the non-fractionated polydistilled on metallic sodium, are introduced. mers Present y y exammatlon) a h gh ry mllini y One of the following catalysts prepared immediately Of the type illustrated in the drawing (Geiger registration before starting the tests at -30 C. under nitrogen is then 0f the Spectrum of P1 Powdery y regular aitelhated added depending on the particular example (see Table 1): ethyl y p P Y (1) Catalyst prepared by adding 9.0 millimols of tri-n- In Examp 5 and 5 the Pfedllcts are P hexyl aluminum to a solution of 3.6 millimols of vanay rich in eyeiopehtehe the Y ditfhaetioh p dium tetrachloride in 30 cc. of anhydrous n-heptane; or um, registered With e Geiger counter, does not reveal (2) A catalyst prepared by adding 14 millimols of dithe Preeehee 0t 3 elysteliihity the yp deriving from ethyl aluminum monochloride to a solution of 2.8 Inillieeqllehees of ethylene monomeric unitsmols of vanadium triacetylacetonate in 30 cc. of anhy- The corresponding Spectra of Examples 1 and 4 the drohs toluene contrary, in addition to showing a high crystallinity de- After having introduced cyclopentene and the catalytic living from the Presence of large amounts of alternated system into the polymerization vessel, an absolute total P Y 31150 Show a Weak etystaiiihity due to pressure of 750 torr is adjusted therein at -30 C. by quehees of ethylene monomeric unitsmeans of nitrogen. Agitation is started and the apparatus The etude eopoiymefiletes described in Table 1 are is connected (by opening the stop cock) with a vessel in the form of White P y can he eaSiiY containing radioactive ethylene having a known specific truded at about 200 C. in) filaments can be hotactivity (The radioactive ethylene was used to f ilitat stretched. The X-ray examination of these stretched filaour analysis of the products.) The absolute total pressure Ihehte gives a epeetrum of Oriented fibre Which is y in the reactor is maintained by means a huhhlcr fill d rich in reflections attributable to an alternated ethylenewith butyl phthalate, at values of Sterie Structure- While in spectra of this type obtained from crude co- (l) 850 torr, polymerizate samples prepared according to Examples 2 (2) 800 torr or and 3 (heterogeneous catalyst) a weak cryst-allinity of (3) 775 torr, the type characteristic of polyethylene is also observed,

the spectra of this type obtained from crude copolymeridepending on the particular example. zate samples prepared according to Examples 5 and 6 Therefore, in the polymerization apparatus, there are, (with a catalyst soluble in the reaction medium) do not 9 present any crystallinity of the polyethylenic type but only the crystallinity attributable to the alternated ethylenecyclopentene copolymer.

The crude copolymerizates can be fractionated, e.g. by successive extractions with boiling solvents having a progressively increasing boiling point. The following fractions have been separated from crude copolymerizates obtained according to Example 2:

ether extract n-hex ane extract n-heptane extract n-octane extract extraction residue The crude copolymerizates of Examples 3-6 were separated into the following fractions:

ether extract n-ootane extract extraction residue In one case (Example 1) the crude copolymerizate was fractionated as follows:

the crude copolymerizate was completely dissolved in boiling toluene; after cooling the solution to room temperature the portion of precipitated copolymer was filtered while the solution was dried and the copolymer therein dissolved was recovered.

The following fractions were thus obtained:

toluene extract 00 residue from the toluene extraction The results of the fractionation of the crude copolymerizates of Example 2 to 6 are reported in Table 2.

The extraction residue of Example 2 for instance presents the following properties:

Cyclopentene molar content percent 50 Density at 24 C 1.01 Melting temperature (determined under the microscope) C 183-185 Intrinsic viscosity [7]] at 135 C. in tetrahydronaphthalene 1.01

Solubility:

insoluble (both at room temperature and at the boiling point of the solvent) e.g. in: methanol, diethyl ether, n-octane, acetone, methylethylketone, glacial acetic acid, dioxane, dirnethylformamide and carbon tetrachloride;

soluble at the boiling temperature of the solvent but insoluble at room temperature e.g. in: benzene, toluene, anisol, tetrahydronaphthalene, decahydronaphthalene, ortho-dichloro-benzene and nitrobenzene.

No solvent has been found to be capable of dissolving this copolymer at room temperature, even after a long contact time.

Infra-red examination:

absorption of CH groups in the ring (bands at 6.93

absorption of CH gIOups in the chain (bands at 6.84

1.5 (approximately) an intense band at 13.2,u, attributable to methylenic sequences of two carbons; complete absence of bands between 13.6 .t and 13.9

The fractions obtained by fractionation with boiling solvents (as shown in Table 2), are as follows:

The ether extracts have an oily-waxy consistency. They consist of low molecular Weight amorphous copolymers containing about 50% by mols of cyclopentene. They are therefore alternated cyclopentene-copolymers which do not present any stereoregularity and, therefore, do not exhibit any crystallinity.

The n-hexane extracts have a plastic consistency. They consist of solid copolymers which are substantially amorphous or present a very low crystallinity of the type shown in the drawing. Their cyclopentene content by mols is about 50%; their density is: d =0.98.

The n-heptane extracts consist of solid products which by X-ray examination present a low crystallinity of the type shown in the drawing. Their cyclopentene content by mols corresponds to about 40%.

The n-octane extracts consist of solids which by X-ray examination exhibit a high crystallinity of the type shown in the drawing, accompanied by a considerable crystallinity of the polyethylene type. Their cyclopentene content by mols varies from 35 to In this copolymer there is present most of the ethylene which in the crude copolymerizate was in excess of the unitary ethylene/cyclopentene molar ratio.

The extraction residues are white powders. They have a very high crystallinity (higher than 50%) of the type shown in the drawing and are completely free from crystallinity of the polyethylene type. Their cyclopentene content by mols is exactly 50%. They are therefore pure alternated ethylene/cyclopentene copolymers having a high regularity of steric structure.

which are characteristic of methylenic sequences of more than 2 carbon atoms. X-ray examination on powders (see the drawing):

the main reflections lay at lattice distances of 5.83 A.,

4.92 A. and 4.37 A. X-ray examination on stretched and annealed fibers:

identity period along the fiber axis of 9.0 A.i0.2

orthorhombic elementary cell; lattice constants 11 8.75 A.; 12:7.83 A.; 0:9.0 A. :02.

TABLE 3 Octane extraction residue of the Example 1 2 3 4 5 6 [1 at C. in tetrahydronaphthalene The sample obtained according to Example 1 was fractionated with toluene according to the procedure already described:

the toluene extract amounting to 24% by weight of the crude polymerizate, is a soft, rubbery-plastic product having a cyclopentene molar content of 49%. It consists essentially of an amorphous alternated ethylene/ temperatures slightly higher than 100 C. into flexible transparent laminae.

TABLE 4.COPOLYMERIZATION OF CYOLOHEXENE WITH ETHYLENE [1;] at 135 C. Cyclohexene CZ'H4 Copolymcr in tetramolar content Example Catalyst pressure, Solvent Cyclohcxene obtained, hydroot the crude Torr g. naphthalene copolymerlzatc, percent 3 VCli/AKhcxyl); 50 30 em. n-heptane. 10.0 1)2.2 ernfi) (-0.122 1.38 1.01 13,6

mo do 25 d0. ..-...-....d 0. 56 1. 04 19.5 V(acetylucetonate)alAlEtzCl.-- 50 3O emfi toluene ..do... 0. 80 1. 25 13, 2 11 VCh/AMhexyl); 12.5 45.0 cm. 0.24 0. 68 26.5

1 Determined by radiochemical analysis and confirmed by infra-red spectrophotometry.

The toluene residue, amounting to 76% by weight of the crude polymer, is a powdery product having a melting temperature at 180l85 C. Its intrinsic viscosity determined in tetrahydronaphthalene at 135 C. is 1.84. It presents the following characteristics determined on a standard moulded specimen (dumbell):

Yield point kg./cm. 200205 Tensile strength kg./cm. 480 Elongation at break percent 360 Shore D hardness 65 Rockwell hardness 51 Its cyclopentene molar content is 40%.

The products can be moulded or spun at temperatures from 10 to 50 C. above their melting or softening temperatures.

EXAMPLE 7 The copolymerization of ethylene with cyclopentene is carried out as described in Example 5 by operating in the absence of diluting medium, i.e., replacing all the solvent with cyclopentene which therefore is used in a total amount of 30 cc. Then proceeding as described in Examples 1 to 6, 0.6 g. of a crude polymerizate having an intrinsic viscosity of 0.98 are obtained. It exhibits a high crystallinity of the type characteristic for the aforementioned alternated ethylene/cyclopentene copolymer, and no crystallinity of the polyethylene type.

The extraction of this crude polymerizate with ether and n-octane leaves an insoluble residue amounting to 61.2% of the total.

The intrinsic viscosity of the residue determined in tetrahydronaphthalene at 135 C., is 1.07. It presents an X-ray diifraction spectrum very similar to that shown in the drawing.

Its other properties also correspond to those of the n-oct ane residue of Example 2.

EXAMPLES 8-11 The copolymerization apparatus and the procedure are l the same as those described for Examples 1 to 6.

The runs are carried out with cyclohexene (instead of cyclopentene), purified by distillation on metallic sodium. The polymerization temperature (-30 C.) and time (7 hours) are those used with cyclopentene (Examples 1 to 6). The polymerization conditions are illustrated in Table 4. (In Example 11 no diluting medium is used; the liquid phase consists exclusively of cyclohexene.)

The products obtained under the conditions reported in Table 4 consist of crude ethylene-cyclohexene copolymeriz-ates the cyclohexene content of which decreases by increasing the ethylene partial pressure used in the copolymerization. The crude copolymerizates have an X- ray diffraction spectrum in which, near to a low crystallinity of the polyethylenic type, there is also 'a maximum characteristic of amorphous copolymers and the position of which is clearly different from the maxim-um characteristic of polyethylene.

The said ethylene-cyclohexene copolymers are in the form of white powders which can be easily molded at The crude copolymerizates of ethylene with cyclohexcne can be fractionated e.g., by successive extractions with boiling solvents having increasing boiling points. The following fractions have been separated:

ether extract n-hexane extract n-heptane extract extraction residue The results obtained by fractionation of the crude copolymerizates of Examples 8 to 11 are reported in Table 5.

TABLE 5.FRACTIONATION OF ETHYLENE-CYCLOHEX- ENE COPOLYMERIZATES Example (ac- Ether exn-Hexane n-Heptane Extraction cording to tract, extract, extract, residue,

Table 4) percent by percent by percent by percent by weight weight weight weight The fractions of Table 5, have the following composition:

the ether extracts have an oily consistency. They consist of low molecular weight amorphous ethylene-cyclohexene copolymers.

The hexane extracts have a plastic consistency. They consist of ethylene-cyclohexane copolymers containing 30 to 40% of cyclohexene by mols. By X-ray examination they present a spectrum in which the crystallinity bands are practically absent and the amorphous maximum is characteristic of smectic polymers. These copolymers can be easily hot molded, giving transparent laminae. They can also be extruded to stretchable fibers. The fiber spectrum presents a very low crystallinity of the polyethylene type. The copolymer extractable with n-hex'ane contains large amounts of sequences of the type:

The n-heptane extracts have a powdery consistency. They consist of ethylene-cyclohexene copolymers containing 10% to of cyclohexene by mols. Their X- rays spectrum can be attributed to the presence of sequence of alternating ethylene-cyclohexene copolynier having a partially ordered steric structure.

The copolymers of the extraction residues present a high crystallinity of the polyethylene type. They consist of ethylene-cyclohexene copolymers containing 3 to 10% of cyclohexene by mols.

EXAMPLE 12 The copolymerization of ethylene with cycloheptene is carried out in the apparatus and with the technique described in Examples 1 to 6.

19.2 g. (0.2 mol) of cycloheptene, distilled on metallic sodium; and a catalyst prepared at (3., according to the technique described in Examples 1 to 6, from 3.6

113 millimols of vanadium tetrachloride and 9.0 millimols of aluminum tri'hexyl, and 77 cc. of nheptane are introduced into the reactor.

The partial ethylene pressure maintained in the copolymerization apparatus is 100 torr and the temperature is -30 C. The copolymerization time is 7 hours.

After 7 hours the copolymerization is stopped and the reaction product is poured into 500 cc. of methanol containing cc. of 38% hydrochloric acid. After some hours the precipitated copolymer is filtered, washed with boiling methanol and dried under a pressure of 12 torr at 60 C.

3.6 g. of an ethylene-cycloheptene copolymerizate consistin' of a slightly rubbery but not tacky mass are thus obtained.

The content of ethylene units, determined by radiochemical analysis, of the copolymerizate is 35.7% by weight (65.5% by mols) and its content of cycloheptene units is 64.3% by Weight (34.5% by mols).

The X-rays examination of the total crude copolyrnerizate reveals the presence of weak crystallinity bands attributable to polyethylene sequences in the copolyrner, and of a Wide intense band, characteristic of amorphous polymers, which can not be ascribed to polyethylene sequences.

The intrinsic viscosity of the crude copolymerizate determined in tetrahydronaphthalene at 135 C., is 1.8. This is a true ethylcne-cycloheptene copolyrner as is demonstrated by the fact that, by extraction with boiling solvents, it was not possible to isolate fractions consisting of one of the two homopolymers; on the contrary fractions containing characteristic amounts of units deriving from the two monomers are always obtained.

The crude copolymerizate was fractionated by successive extractions with boiling solvents.

The following fractions were thus obtained:

ether extract (fraction soluble in boiling diethyl ether);

n-hexane extract (fraction insoluble in boiling diethylether but soluble in boiling n-hexane);

n-heptane extract (fraction insoluble in boiling ethyl ether and n-hexane but soluble in boiling n-heptane);

benzene extract (fraction insoluble in boiling diethyl ether, n-hexane and n-heptane but soluble in boiling benzene);

benzene residue (fraction insoluble in all the aforementioned solvents).

The percentages of these fractions in respect of the total are:

Percent Ether extract 5.4 n-Hexane extract 3.6 n-Heptane extract 7.7 Benzene extract 69.4 Benzene residue 13.9

The benzene residue is a fibrous white substance having an intrinsic viscosity, determined in tetrahydronaphthalene at 135 C., of 3.2.

From the radio-chemical examination, the benzene extract consists of a copolyrner containing 96% by mols of ethylene units and 4% by mols of cycloheptene units. By X-rays examination it shows only the crystallinity band attributable to sequences of methylene groups.

The benzene extract is a fibrous slightly rubbery mass. It has an intrinsic viscosity, determined in tetrahydronaphthalene at 135 C., of 1.4. From the radiochemical examination, it consists of a copolymer containing 58% by mols of ethylene units and 42% by mols of cycloheptene units. It is insoluble, both at room temperature and at the boiling point, in various solvents, such as nhexane, n-heptane, diethyl ether, methanol, n-butanol, acetone, methylethylketone, ethylacetate, and dimethylformamide. It is insoluble or scarcely soluble at room temperature but soluble at the boiling point in the following solvents:

benzene n-octane tetrahydrofurane anisole chlorobenzene It is on the contrary soluble, both at room temperature and at the boiling point, in some solvents including cyclohexane and carbon tetrachloride.

The benzene extract softens at temperatures above about 60 C.; complete melting however occurs at about 160 C.

The X-rays diffraction spectrum determined on powders (CLlKrx radiations, recorded with a Geiger counter) previously annealed in n-hexane or on filaments stretched and annealed in water reveals the presence of intense crystallinity bands at:

29=8.75 (md.);16.5 (f.);18.65 ((1.)

which correspond to lattice distances of 10.10 A.; 5.37 A. and 4.76 A. respectively.

None of these bands is attributable to polyethylene sequences.

On the basis of the identity period of 9.0 A.- *:0.2 (obtained by X-rays examination of filaments stretched and annealed in water at 60 C.) said crystallinity bands are attributable to the presence, in the copolyrner of the benzene extract, of a high percentage by mols) of sequences characterized by the regular alternating succession of ethylene and cycloheptene units in which the tertiary carbon atoms of the main chain are sterically ordered.

The structure of said sequences is schematically represented in the following model of a portion of the main chain:

The infra-red spectrophotometric examination of hotmolded laminae shows that the cycloheptene units are contained in this copolyrner in the form of cycloheptane rings.

No band attributable to double bonds can be noted in said spectrum as would occur if the copolyrnerization of the cycloheptene had taken place by opening of the rings instead of by opening of cyclo-olefin double bonds.

Moreover, the existence of an intense band at 6.88 (spectrum in calcium fluoride) reveals the presence of methylenic groups in cycles. These analytical results confirm the above structure of a copolyrner essentially characterized by the regular alternation of ethylene and cycloheptene units.

The n-heptane extract of the copolymer is a white rubbery mass having an intrinsic viscosity, determined in tetrahydronaphthalene at C., of 1.9.

By radiochemical examination it consists of a copolyrner containing 70.5% by rnols of ethylene units and 29.5% by mols of cycloheptene units.

By X-rays examination it shows weak crystallinity bands due to polyethylene sequences and a wide intense absorption at 23: about 17 (CuKa radiations) attributable to the presence of a certain percentage of sequences in which ethylene units alternate successively with cycloheptene units in the main chain, but the sequences are not sufficiently long to permit their crystallization.

The n-hexane extract of the crude .copolymerizate is a waxy white mass having an intrinsic viscosity, determined in tetrahydronaphthalene at 135 C., of 0.45. On the basis of the radiochemical examination it consists of 55% of ethylene units and 45% of cycloheptene units.

By X-rays examination it consists essentially of an alternating ethylene-cycloheptene copolyrner having low 15 crystallinity. Crystallinity bands at 29=8.75 (md.); 16.5".(f.);18.65 (d.).

It distinguishes from the corresponding alternating crystalline copolymer of the benzene extract by having a lower steric purity of the tertiary carbon atoms and a lower molecular weight, both factors determining its greater solubility in organic solvents.

The ether extract consists of low molecular weight oily amorphous copolymers of ethylene and cycloheptene, having an intrinsic viscosity, determined in tetrahydronaphthalene at 135 C., of 0.3.

The content of ethylene units amount to 72% by mols and that of cycloheptene units to 28% by mols.

EXAMPLE 13 The copolymerization of ethylene with cycloheptene is carried out as described in Example 12, except that a partial pressure of radioactive ethylene of 50 torr is used.

By proceeding as described in Examples 1-6 and 12, 0.95 g. of an ethylene-cycloheptene copolymerizate having an ethylene units content (determined by radiocherm'cal analysis) of 33% by weight (63% by mols) and a cycloheptene units content of 67% by Weight (37% by mols), and having an intrinsic viscosity, determined in tetrahydronaphthalene at 135 C., of 1.5 are obtained.

The copolymerizate, apart from the slightly higher content of cycloheptene units and a lower intrinsic viscosity, has properties very similar to those of the crude copolymerizate described inExample 12.

By fractionating the copolymerizate according to the procedure described in Example 12, the following fractions are obtained:

Percent 01 Percent ethyl- Percent cyclo- Extrnct total by ene units heptene units weight (mols) (mols) Ether 6. O 75 27 n-Hexane-.. 22. 5 52 48 u-Heptene-.- 17. 64 36 Benzene"... 47. 7 58 42 Benzene residue- 6. 7 95 EXAMPLE 14 The copolymerization of ethylene with cyclopentene is carried out as described in Examples 1 to 6 by using 0.2 mol of cyclopentene and a catalyst prepared at -30 C. as described above from 3.6 mm. of vanadium triacetylaeetonate, 18 mm. of aluminum diethylmonochloride and 60 cc. of anhydrous toluene.

Copolymerization conditions:

Temperature C -30 Time hours 7 Partial pressure of radioactive ethylene torr 50 Results:

Crude copolymer amount g 1.46 Ethylene units content (determined by radiochemical analysis) (:=50% by mols) percent by wt 23 Intrinsic viscosity in tetrahydronaphthalene at 135 C. 0.7

The crude copolymer is fractionated by extraction with 16 boiling solvents. The results obtained are reported in the following table:

TABLE 6 Percent pro- Ethylene X-rays Fraction portion on units content, examination crude percent by copolymer mols Ether extract 12. 0 Amorphous. n-Hexane extract. 16.8 50 Smeetic. n-Heptane extraet 26.9 51 Do. Benzene extract. 42. 5 51. 5 Crystalhne. Residue 1. 5 Not determined.

1 Not determined.

The technique described in Examples 1-6 was employed for the copolymerization of ethylene with ciscyclo-octene, using:

0.2 mol (22.0 g.) of cis-cyclo-octene distilled on metallic sodium;

a catalyst freshly prepared at 30 C. from 3.6 millimols of vanadium acetylacetonate and 18 millimols of aluminium diethyl monochloride in 60 cc. of toluene according to the technique described in Examples 4-6.

The partial ethylene pressure used is torr, the copolymerization time 7 hours, and the copolymerization temperature 30 C.

An ethylene-cis-cyclo-octene copolymerizate (0.61 g.) was thus obtained. It has a plastic consistency and a content of ethylene units (determined by radiochemical analysis) of 40% by weight (72.4% by mols) and a content of cis-cyclo-octene units of 60% by weight (27.6% by mols).

The intrinsic viscosity, determined in tetrahydronaphthalene at C., was 1.2.

By X-rays examination it presents a wide maximum characteristic of amorphous copolymers, accompanied by a weak crystallinity of the type which is characteristic of polyethylene sequences.

The infra-red spectrophotometric analysis reveals the presence of cyclo-octane units (band at 8.90 in the spectrum recorded with CaF optics) and the absence of double bonds.

The cis-cyclo-octane units are therefore originated by opening of the olefinic double bond and not by opening of the cyclo-octene rings.

By extraction with boiling solvents according to the techniques described in Examples 1-6 and 12, the following fractions can be separated from the crude copolymerizate:

Percent of Percent Percent cis- Extract total by ethylene units cyelooctene weight (mols) units (mols) Ether 31 69 31 n-Hexane.-. 34 68 32 n-Heptane 19. 4 75. 5 24. 5 n-Heptane residue 15. 4 73 27 The n-heptane extract is a white mass the X-rays examination of which reveals the presence of amorphous copolymer and of sequences of crystalline polyethylene.

The n-heptane residue shows the same characteristics as the n-heptane extract.

EXAMPLE 16 By the technique described in Exampels 1-6, the copolymerization of ethylene with cis-cyclo-octene is carried out using:

0.2 mol (22.0 g.) of cis-cyclo-octene distilled on metallic sodium a catalyst freshly prepared at 30" C. from 3.6 millimols of vanadium tetrachloride and 9.0 millimols of aluminum tri-n-hexyl in 77 cc. of n-heptane; and

a partial ethylene pressure of 100 torr, a copolymerization time of 7 hours, and a copolymerization temperature of 30 C.

The crude copolymerizate which was isolated (1.35 g.) was a White powdery material.

It has a content of ethylene units (determined by radiochemical analysis) of 75% by weight (92% by mols) and a content of cis-cyclo-octene units of 25% by Weight (8% by mols), and an intrinsic viscosity, determined in tetrahydronaphthalene at 135 C., of 4.6.

By X-rays examination this copolymerizate shows intense bands of crystallinity attributable to polyethylene sequences. The infra-red spectrophotometric examination shows that the cis-cyclo-octene units are present in the co polymer in the form of cycle-octane rings.

EXAMPLE 17 The copolymerization apparatus consists of a 250-cc. three necked flask provided with an agitator, a dropping funnel and a side tube for feeding nitrogen.

Into this apparatus kept under anhydrous nitrogen at the temperature of -60 C., 100 cc. of a n-heptane and a catalytic mixture previously prepared in a flask at 30" C. by reacting 3.6 millimols of VCl dissolved in 30 cc. anhydrous n-heptane and 9.00 millimols of Al(n-C H are introduced.

Ethylene is then fed at the flow rate of l/h.

At the same time, through the dropping funnel cooled to 60 C., a solution of 10 g. of cyclobutene in 50 cc. n-heptane is added dropwise.

The dropping rate is 10 drops of solution per minute.

The total solution therefore added within about 3 hours. At the end of the introduction of cyclobutene, the ethylene feeding is stopped and the apparatus is still kept at 60 C. for 1 hour while agitating.

The reaction product is then poured into 1 litre methanol containing 10 cc. of concentrated hydrochloric acid.

The precipitated copolymer is washed with methanol and vacuum dried at about +50 C.

28 g. of ethylene-cyclobutene copolymer having a molar ethylene content of 77% are thus obtained.

By X-rays examination the copolymer exhibits the crystallinity characteristic for polyethylene sequences.

EXAMPLE 18 250 cc. three-necked flask provided with an agitator, a dropping funnel with outer cooling jacket, and a gas inlet tube is cooled to 60 C.

In the apparatus air is replaced by dry nitrogen and 100 cc. of anhydrous toluene are introduced. A catalytic mixture previously prepared at 30" C. according to the modalities of Examples 4 to 6 from 40 cc. of anhydrous toluene, 3.6 millimols of vanadium acetylacetonate and 18 millimols aluminum diethyl monochloride is then added. Agitation is started and the whole is kept at 60 C.

Cyclobutene and ethylene are then introduced almost contemporaneously during a period of 3 hours according to the following technique:

a solution of 3.9 g. (73 millimols) of cyclobutene in 50 cc. of anhydrous toluene is placed in the dropping funnel cooled to 78 C., and is introduced dropwise during 3 hours into the reaction flask. A flow of 0.50 litre/hour of ethylene marked radioactively with C is bubbled at the same time through the solution. All ethylene introduced is absorbed by the reaction mixture. As soon as all cyclobutene has been introduced into the reaction mixture, the introduction of ethylene is stopped. The total ethylene amount introduced is 1.88 g. (67 millimols).

After introduction of the two monomers the whole is agitated at 60 C. for further two hours.

The reaction is then stopped by adding 10 cc. of methanol. The flask is left to reach the room temperature and the gelatinous mixture is poured in 1 litre of methanol containing 10 cc. of 38% hydrochloric acid. The copolymer obtained is filtered, washed with boiling methanol and dried under reduced pressure.

5.15 g. (88% of the monomers introduced) of a white powdery product which is plastic but not tacky are thus obtained.

This product has an intrinsic viscosity, determined in tetrahydronaphthalene at C. of 0.8. On the basis of the radiochernical analysis the crude copolymer appears to consist of 33.4% by weight (49.2% by mols) of units deriving from ethylene and 66.6% by weight (50.8% by mols) or units deriving from cyclobutene. The infrared examination does not reveal the presence of double bonds in the copolymer, thus showing that the cyclobutenic units therein contained are present in the form of cyclobutane rings.

The X-rays examination shows that the copolymer is completely amorphous.

The copolymer is insoluable at room temperature, and partially insoluble also at the boiling point of the solvent, e.g., in diethyl ether, tetrahydrofurane, n-heptane, methylethylketone, carbon tetrachloride, acetophenone and anisole. It is soluble e.g., in boiling toluene and tetrahydronaphthalene.

The crude copolymer softens at about 120-146 C. By heating to C. it can be easily moulded and extruded into filaments.

The results We obtain by repeating the foregoing examples with the following catalyst systems are similar to those shown in the examples:

VCl VCl VBr VOCl TiCl TiBr (CH C0O) TiCl /Al alkylmonohalides or alkyls of Al, Be, Zn, Na and Li, in which the alkyl groups contain 1 to 18 carbon atoms;

V triacetylacetonate; vanadyldiacetylacetonate;

V chlorodiacetylacetonates or alkylorthovanadates (in which the alky group contain from 1 to 6 carbon atoms)/ Al dialkylmonohalides in which the alkyl groups contain from 1 to 8 carbon atoms;

TiCl VCl /Al trialkyl or dialkyl monohalides in which the alkyl groups contain from 1 to 8 carbon atoms.

The solvents used for fractionating the crude copolymerizate to separate the different kinds of copolymers comprised therein were determined by us empirically, on the basic of the melting temperature of the different copolymers. In general, the crystalline copolymers which have the stereoregular alternating structure are dissolved by aliphatic hydrocarbon solvents having a boiling point higher than the melting point of the copolymer. It is recognized by us that the different copolymers we have separated and characterized may be separated from the crude using solvents other than those shown in our examples, and which could also be determined empirically. Therefore, we contemplate that, in practicing our invention, some variations may be made in respect to the 19 solvents used for the fractionation which variations would be Within the scope of our invention and the appended claims:

What is claimed is:

1. Normally solid copolymers of ethylene and a cycloolefin selected from the group consisting of cyclopentenc and cycloheptene consisting essentially of linear macromolecules substantially made up of a regular 1:1 alternating succession of polymerized ethylene units and polymerized units of the selected cycloolefin in which latter units the tertiary carbon atoms have a regular steric configuration whereby, the copolymers exhibit, on X-ray examination at room temperature, practically no crystallinity of polyethylenic type but do exhibit at least 50 percent of crystallinity resulting from the regularly alternating arrangement of the polymerized ethylene units and the polymerized cycloolefin units in which the tertiary carbon atoms have the regular steric configuration, the copolymers having an identity period of 90:02 A. determined by X-ray examination of stretched, annealed fibers thereof.

2. Copolymers according to claim 1 further characterized in being copolymers of ethylene with cyclopentene, having a melting point of 180 to 185 C. and lattice distances of 5.83 A., 4.92 A. and 4.37 A., respectively.

3. Copolymers according to claim 1, further characterized in being copolymers of ethylene 'with cycloheptene having a melting point of about 160 C. and lattice distances of 10.10 A., 5.37 A. and 4.76 A., respectively.

4. The process for producing copolymers as defined in claim 1, which process comprises polymerizing a mixture of ethylene and the selected cyclo-olefin in an ethylene/ cyclo-olefin molar ratio of 25:1 to 200:1 in liquid phase, at a temperature between -80 C. and +10 C., and in contact with a catalyst which is colloidally dispersible to completely soluble in the liquid phase in which the copolymerization is carried out and which is prepared by mixing a hydrocarbon-soluble vanadium compound with an organometallic compound of a metal belonging to one of Groups I to III inclusive of the Periodic Table according to Mendeleef, and recovering the copolymers as defined in claim 1 from the resulting total copolymerizate by fractional dissolution.

5. The process according to claim 4, characterized in that the liquid phase consists of the cyclo-olefin.

6. The process according to claim 4, characterized in that the copolymerization is carried out in an inert hydrocarbon solvent selected from the group consisting of aliphatic and aromatic hydrocarbons.

7. The process according to claim 4, characterized in that the catalyst is prepared by mixing the vanadium compound with an aluminum compound selected from the group consisting of aluminum trialkyls and dialkyl aluminum halides.

8. Thermoplastic compositions comprising copolymers as defined in claim 1.

9. Manufactured shaped articles comprising copolymers as defined in claim 1.

10. Fibers comprising a copolymer as defined in claim 1.

11. Films comprising copolymers as defined in claim 1.

References Cited UNITED STATES PATENTS 7/1960 Schmerling 260-93] 10/1962 Vandenberg 26088.2

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No 3 ,385 ,840 May 28 1968 Giulio Natta et al.

It is certified that error appears in the above identified patent and that said Letters Patent are hereby corrected as shown below:

Column 8, lines 67 and 68, "rich in reflections attributable to an alternated ethylene-steric structure." should read rich in reflections attributable to an alternated ethylenecyclopentene copolymer, having a high regularity of steric structure.

Signed and sealed this 11th day of November 1969.

(SEAL) Attest:

Edward M. Fletcher, Jr. WILLIAM E. SCHUYLER, JR.

Attesting Officer Commissioner of Patents 

1. NORMALLY SOLID COPOLYMERS OF ETHYLENE AND A CYCLOOLEFIN SELECTED FROM THE GROUP CONSISTING OF CYCLOPENTENE AND CYCLOHEPTENE CONSISTING ESSENTIALLY OF LINEAR MACROMOLECULES SUBSTANTIALLY MADE UP OF A REGULAR 1:1 ALTERNATING SUCCESSION OF POLYMERIZED ETHYLENE UNITS AND POLYMERIZED UNITS OF THE SELECTED CYCLOOLEFIN IN WHICH LATTER UNITS THE TERTIARY CARBON ATOMS HAVE A REGULAR STERIC CONFIGURATION WHEREBY, THE COPOLYMERS EXHIBIT, ON X-RAY EXAMINATION AT ROOM TEMPERATURE, PRACTICALLY NO CRYSTALLINITY OF POLYETHYLENIC TYPE BUT DO EXHIBIT AT LEAST 50 PERCENT OF CRYSTALLINITY RESULTING FROM THE REGULARY ALTERNATING ARRANGEMENT OF THE POLYMERIZED ETHYLENE UNITS AND THE POLYMERIZED CYCLOOLEFIN UNITS IN WHICH THE TERTIARY CARBON ATOMS HAVE THE REGULAR STERIC CONFIGURATION, THE COPOLYMERS HAVING AN IDENTITY PERIOD OF 9.0$0.2 A. DETERMINED BY X-RAY EXAMINATION OF STRETCHED, ANNEALED FIBERS THEREOF. 